Tropical Depths
Land (Rare)

At the beginning of your end step, if you didn't cast any spells this turn, Tropical Depths deals 1 damage to you.

Tap: Add BG to your mana pool. Tropical Depths doesn't untap during your next untap step.

BG: Tropical Depths becomes a 2/1 green and black Leech creature until end of turn. It's still a land.

Christopher Avon